US3823453A - Method of manufacturing an indirectly heated cathode and cathode manufactured according to this method - Google Patents
Method of manufacturing an indirectly heated cathode and cathode manufactured according to this method Download PDFInfo
- Publication number
- US3823453A US3823453A US00310347A US31034772A US3823453A US 3823453 A US3823453 A US 3823453A US 00310347 A US00310347 A US 00310347A US 31034772 A US31034772 A US 31034772A US 3823453 A US3823453 A US 3823453A
- Authority
- US
- United States
- Prior art keywords
- metal
- cathode
- cap
- percent
- layer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
- H01J1/02—Main electrodes
- H01J1/13—Solid thermionic cathodes
- H01J1/20—Cathodes heated indirectly by an electric current; Cathodes heated by electron or ion bombardment
- H01J1/26—Supports for the emissive material
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
- H01J9/02—Manufacture of electrodes or electrode systems
- H01J9/04—Manufacture of electrodes or electrode systems of thermionic cathodes
Definitions
- the invention relates to a method of manufacturing an indirectly heated cathode in which a nickel cap as a support of the emissive material is welded to one end of a metal cylinder which is coated with a black layer.
- the invention furthermore relates to a cathode obtained according to said method.
- black layer can be obtained in a simple manner by oxidizing the material of the cylinder which usually consists of nickel or of a nickel-chromium alloy, before the cap is provided.
- the surface of the cylinder 1 is dipped in a suspension containing, for example, 2 litres of methylisobutylketonein which 160 g of nitrocellulose have been dissolved and in which 720 g of tungsten powder and 480 g of A1 have been suspended.
- the layer is then dried and sintered in a hydrogen atmosphere at l,200 C for 60 minutes.
- the aluminium oxide prevents the fonnation of an alloy between the tungsten and the nickel of thesubstratum which would decrease the radiation of the layer 2.
- a long cylindrical tube is preferably coated and after sintering cut into parts-of the desired length.
- a nickel cap 3 is slid over emissive layer 4 is provided on the cap 3.
- the cap comthe method according to the invention. For example,
- the cylinder is previously coated with a layer of a suspension comprising one or more suitable refractory metals and one or more metal oxides in powder form, after which the layer is dried and sintered in a reducing atmosphere, the nickel cap is slid over one end of the cylinder coated with the sintered layer and is then welded to said end.
- the sintered layer generally still comprises metal oxide, it has been found that welding does not present any diffi-' culties.
- Alayer consistingof a mixture of tungsten and aluminium oxide has proved to be very suitable.
- a layer of molybdenum and aluminium oxide has also proved to be suitable.
- the quantity of tungsten in the suspension for the layer to be provided may be from 40 to 90 percent by weight, the quantity of aluminium oxide from 60 to 10 percent by weight.
- the suspension may also comprise tungsten or molybdenum and their oxides.
- Reference numeral 1 in the FIGURE denotes a chromium-nickel cylinder (20 percent by weight Cr, 80
- the layer 2 comprises 40 percent by weight of A1 0 powder, it has beenfound that welding of the cap 3 does not present any difficulties. A heating member is afterwards provided in the cylinder 1. It has been found that the layer 2 maintains a constant black colour throughout the life of the cathode.
- cathodes which havebeen shaped in a different manner can also be manufactured by means of the cap 3 may be provided with a flange for the connection in the electrode system.
- a method of manufacturing an indirectly heated cathode comprising the steps of providing a metal first body and a nickel cap member, coating said metal first body with a layer consisting essentially of at least one refractory metal and at least one metal oxide in powder form, sintering said coated first body in a reducing atmosphere to provide a black layer thereon, and then welding said nickel cap at one end of said coated first body, whereby said nickel cap provides a support for emissive material for said cathode.
- An indirectly heated cathode comprising a metal first body coated with a sintered metal layer essentially consisting of from 60 to 10 percent by weight of metal oxide and the balance a metal, further comprising a cap welded to said first body over the sintered layer, and an emissive material provided on said'cap.
Abstract
A cathode cap is welded to a metal cylinder over a black sintered metal layer which contains from 60 to 10 percent by weight of metal oxide and which covers the whole cylinder.
Description
United States Patent 19 Van Stratum et al.
[75] Inventors: Antonius Johannes Alberta Van Stratum; Theodorus Hendrikus Weekers, both of Emmasingel, Eindhoven, Netherlands [73] Assignee: U.S. Philips Corporation, New
7 York, NY.
22 Filed: Nov. 29, 1972 21 Appl. No.: 310,347
[30] Foreign Application Priority Data Dec. 16, 1971 Netherlands 0 7117226 [52] U.S. Cl. 29/2514, 29/484, 313/337 [51] Int. Cl. H0lj 9/00 [58] Field of Search 29/2513, 2514,484, 488,
[ July 16, 1974 [56] References Cited UNITED STATES PATENTS 1,897,933 2/1933 Guthrie et a1 117/49 X 2,726,308 12/1955 Cinamon...
2,970,204 l/1961 Piceu et al..
2,978,606 4/1961 Kahl 3,535,757 10/1970 Nestleroth et a1. 29/25.]4
Primary Examiner-Roy Lake Assistant Examiner-4. W. Davie Attorney, Agent, or Firm-Frank R. Trifari [57 ABSTRACT A cathode cap is welded to a metal cylinder over a black sintered metal layer which contains from 60 to 10 percent by weight of metal oxide and which covers the whole cylinder.
4 Claims, 1 Drawing Figure METHOD or MANUFACTURING AN INDIRECTLY The invention relates to a method of manufacturing an indirectly heated cathode in which a nickel cap as a support of the emissive material is welded to one end of a metal cylinder which is coated with a black layer. The invention furthermore relates to a cathode obtained according to said method.
It is known that a short heating time can be obtained in an indirectly heated cathode consisting of a nickel cap which supports the emitting material and which is welded to a metal cylinder, if the innersurface and the outer surface of the cylinder are coated with a black layer. The black layer on the inside rapidly absorbs thermal energy from the filament, while the black outside radiates much thermal energy at high temperature so that a comparatively large heating energy is required to keep the cathode at the emission temperature. This high thermal energy ensures a short heating time. The
black layer can be obtained in a simple manner by oxidizing the material of the cylinder which usually consists of nickel or of a nickel-chromium alloy, before the cap is provided. l l
The drawback, however, is that the end to which the nickel cap is to be welded must first be'cleaned since welding of the cap to the oxidelayer is not readily possible. This cleaning, however, is time-consuming.
The oxidation after the cap has been welded to the cylinder is disadvantageous since the cap also oxidizes asa result of which the reducerswhich are present in the nickel of the cap are converted into oxides, which produces emission difficulties. 1
I The drawbacks of the said methods can be avoided percent by weight Ni) which is coated with a sintered black layer 2 consisting of 60 percent by weight of tungsten and 40 percent by weight of aluminium oxide.
For that purpose, the surface of the cylinder 1 is dipped in a suspension containing, for example, 2 litres of methylisobutylketonein which 160 g of nitrocellulose have been dissolved and in which 720 g of tungsten powder and 480 g of A1 have been suspended. The layer is then dried and sintered in a hydrogen atmosphere at l,200 C for 60 minutes. The aluminium oxide prevents the fonnation of an alloy between the tungsten and the nickel of thesubstratum which would decrease the radiation of the layer 2. A long cylindrical tube is preferably coated and after sintering cut into parts-of the desired length. A nickel cap 3 is slid over emissive layer 4 is provided on the cap 3. The cap comthe method according to the invention. For example,
if, according to the invention, the cylinder is previously coated with a layer of a suspension comprising one or more suitable refractory metals and one or more metal oxides in powder form, after which the layer is dried and sintered in a reducing atmosphere, the nickel cap is slid over one end of the cylinder coated with the sintered layer and is then welded to said end. Although the sintered layer generally still comprises metal oxide, it has been found that welding does not present any diffi-' culties. Alayer consistingof a mixture of tungsten and aluminium oxide has proved to be very suitable. A layer of molybdenum and aluminium oxide has also proved to be suitable. The quantity of tungsten in the suspension for the layer to be provided may be from 40 to 90 percent by weight, the quantity of aluminium oxide from 60 to 10 percent by weight. However, the suspension may also comprise tungsten or molybdenum and their oxides.
The invention willbe described in greater detail with reference to an embodiment and a drawing the PIO- URE of which is a cross-sectional view through a cathode obtained by meansof the method according to the invention.
Although in addition to tungsten the layer 2 comprises 40 percent by weight of A1 0 powder, it has beenfound that welding of the cap 3 does not present any difficulties. A heating member is afterwards provided in the cylinder 1. It has been found that the layer 2 maintains a constant black colour throughout the life of the cathode.
Although a single embodiment of a cathode has been described, cathodes which havebeen shaped in a different manner can also be manufactured by means of the cap 3 may be provided with a flange for the connection in the electrode system.
What is claimed is: i
l. A method of manufacturing an indirectly heated cathode, comprising the steps of providing a metal first body and a nickel cap member, coating said metal first body with a layer consisting essentially of at least one refractory metal and at least one metal oxide in powder form, sintering said coated first body in a reducing atmosphere to provide a black layer thereon, and then welding said nickel cap at one end of said coated first body, whereby said nickel cap provides a support for emissive material for said cathode. d
2. A method as claimed in claim 1, wherein said first body is thus coated by dipping in a suspension which consists essentially of from 40 to percent by weight of tungsten and from 60 to 10 percent by weight of aluminum oxide.
3. An indirectly heated cathode, comprising a metal first body coated with a sintered metal layer essentially consisting of from 60 to 10 percent by weight of metal oxide and the balance a metal, further comprising a cap welded to said first body over the sintered layer, and an emissive material provided on said'cap.
4. An indirectly heated cathode as defined in claim 3, wherein said metal is at least one of molybdenum and tungsten and said metal oxide is at least one of aluminum oxide, molybdenum oxide, and tungsten oxide.
which the cathode can be con-
Claims (3)
- 2. A method as claimed in claim 1, wherein said first body is thus coated by dipping in a suspension which consists essentially of from 40 to 90 percent by weight of tungsten and from 60 to 10 percent by weight of aluminum oxide.
- 3. An indirectly heated cathode, comprising a metal first body coated with a sintered metal layer essentially consisting of from 60 to 10 percent by weight of metal oxide and the balance a metal, further comprising a cap welded to said first body over the sintered layer, and an emissive material provided on said cap.
- 4. An indirectly heated cathode as defined in claim 3, wherein said metal is at least one of molybdenum and tungsten and said metal oxide is at least one of aluminum oxide, molybdenum oxide, and tungsten oxide.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NL7117226A NL7117226A (en) | 1971-12-16 | 1971-12-16 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3823453A true US3823453A (en) | 1974-07-16 |
Family
ID=19814707
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US00310347A Expired - Lifetime US3823453A (en) | 1971-12-16 | 1972-11-29 | Method of manufacturing an indirectly heated cathode and cathode manufactured according to this method |
Country Status (8)
Country | Link |
---|---|
US (1) | US3823453A (en) |
JP (1) | JPS5228631B2 (en) |
BE (1) | BE792763A (en) |
CA (1) | CA956694A (en) |
DE (1) | DE2258160B2 (en) |
FR (1) | FR2163606B1 (en) |
GB (1) | GB1349128A (en) |
NL (1) | NL7117226A (en) |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3919751A (en) * | 1974-02-08 | 1975-11-18 | Gte Sylvania Inc | Method of making fast warm up picture tube cathode cap having high heat emissivity surface on the interior thereof |
FR2400253A1 (en) * | 1977-08-11 | 1979-03-09 | Sony Corp | METHOD OF MANUFACTURING A CATHODE ASSEMBLY FOR A CATHODIC TUBE |
EP0059491A1 (en) * | 1981-02-26 | 1982-09-08 | Koninklijke Philips Electronics N.V. | Oxide cathode |
US4781640A (en) * | 1985-01-24 | 1988-11-01 | Varian Associates, Inc. | Basket electrode shaping |
US5296781A (en) * | 1990-12-29 | 1994-03-22 | Goldstar Co. Ltd. | Impregnated cathode |
EP0616353A2 (en) * | 1993-03-17 | 1994-09-21 | Kabushiki Kaisha Toshiba | Cathode assembly and method of manufacturing the same |
CN101075515B (en) * | 2007-06-28 | 2011-09-07 | 北京工业大学 | High-curren density heterogeneous beam electron source |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS5739010B2 (en) * | 1973-11-02 | 1982-08-19 | ||
JPS50146466U (en) * | 1974-05-20 | 1975-12-04 | ||
JPH0677435B2 (en) * | 1985-03-18 | 1994-09-28 | 株式会社日立製作所 | Method for manufacturing indirectly heated cathode |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1897933A (en) * | 1928-08-02 | 1933-02-14 | Peoples Gas By Products Corp | Electrode for electron discharge tubes and method of forming the same |
US2726308A (en) * | 1952-02-13 | 1955-12-06 | Cinamon Lionel | Welding method |
US2970204A (en) * | 1958-02-27 | 1961-01-31 | Piceu | Electric welding method and composition |
US2978606A (en) * | 1959-01-02 | 1961-04-04 | Sylvania Electric Prod | Electron discharge device |
US3535757A (en) * | 1968-03-22 | 1970-10-27 | Rca Corp | Method for making cathode assembly for electron tube |
-
0
- BE BE792763D patent/BE792763A/en unknown
-
1971
- 1971-12-16 NL NL7117226A patent/NL7117226A/xx unknown
-
1972
- 1972-11-28 DE DE19722258160 patent/DE2258160B2/en active Granted
- 1972-11-29 US US00310347A patent/US3823453A/en not_active Expired - Lifetime
- 1972-12-08 CA CA158,798A patent/CA956694A/en not_active Expired
- 1972-12-13 JP JP47124419A patent/JPS5228631B2/ja not_active Expired
- 1972-12-13 GB GB5738972A patent/GB1349128A/en not_active Expired
- 1972-12-14 FR FR7244504A patent/FR2163606B1/fr not_active Expired
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US1897933A (en) * | 1928-08-02 | 1933-02-14 | Peoples Gas By Products Corp | Electrode for electron discharge tubes and method of forming the same |
US2726308A (en) * | 1952-02-13 | 1955-12-06 | Cinamon Lionel | Welding method |
US2970204A (en) * | 1958-02-27 | 1961-01-31 | Piceu | Electric welding method and composition |
US2978606A (en) * | 1959-01-02 | 1961-04-04 | Sylvania Electric Prod | Electron discharge device |
US3535757A (en) * | 1968-03-22 | 1970-10-27 | Rca Corp | Method for making cathode assembly for electron tube |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3919751A (en) * | 1974-02-08 | 1975-11-18 | Gte Sylvania Inc | Method of making fast warm up picture tube cathode cap having high heat emissivity surface on the interior thereof |
FR2400253A1 (en) * | 1977-08-11 | 1979-03-09 | Sony Corp | METHOD OF MANUFACTURING A CATHODE ASSEMBLY FOR A CATHODIC TUBE |
US4305188A (en) * | 1977-08-11 | 1981-12-15 | Sony Corporation | Method of manufacturing cathode assembly |
EP0059491A1 (en) * | 1981-02-26 | 1982-09-08 | Koninklijke Philips Electronics N.V. | Oxide cathode |
US4781640A (en) * | 1985-01-24 | 1988-11-01 | Varian Associates, Inc. | Basket electrode shaping |
US5296781A (en) * | 1990-12-29 | 1994-03-22 | Goldstar Co. Ltd. | Impregnated cathode |
EP0616353A2 (en) * | 1993-03-17 | 1994-09-21 | Kabushiki Kaisha Toshiba | Cathode assembly and method of manufacturing the same |
EP0616353A3 (en) * | 1993-03-17 | 1994-11-09 | Toshiba Kk | Cathode assembly and method of manufacturing the same. |
US5543682A (en) * | 1993-03-17 | 1996-08-06 | Kabushiki Kaisha Toshiba | Cathode assembly incorporating a black layer formed from particles having a specified average particle size |
US5762997A (en) * | 1993-03-17 | 1998-06-09 | Kabushiki Kaisha Toshiba | Method of manufacturing a cathode assembly |
CN101075515B (en) * | 2007-06-28 | 2011-09-07 | 北京工业大学 | High-curren density heterogeneous beam electron source |
Also Published As
Publication number | Publication date |
---|---|
DE2258160B2 (en) | 1977-06-02 |
DE2258160A1 (en) | 1973-06-20 |
JPS4866968A (en) | 1973-09-13 |
FR2163606B1 (en) | 1977-04-08 |
CA956694A (en) | 1974-10-22 |
JPS5228631B2 (en) | 1977-07-27 |
FR2163606A1 (en) | 1973-07-27 |
NL7117226A (en) | 1973-06-19 |
BE792763A (en) | 1973-06-14 |
GB1349128A (en) | 1974-03-27 |
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